Vacuum breaking apparatus



y 1954 E. STOSSEL 2,684,075

VACUUM BREAKING APPARATUS Filed April 1'7, 1952 2 Sheets-Sheet 1 INVEN T OR.

E EST STQSSEI.

July 20, 1954 E. STOSSEL VACUUM BREAKING APPARATUS 2 Sheets-Sheet 2 Filed April 17, 1952 INVENTOR. ERNEST $7 Patented July 20, 1954 UNITED. PATENT OFF'l CE.

VACUUM BREAKING APPARATUS Ernestixstossel; San Francisco, Calif.

Application April 17, 1952/, Serial No. 282,763

Claims; (Cl. 137-103) The present invention, relates to a vacuum breaking apparatus. More particularlv'thepres-- ent invention relates to a vacuum breaking appa-- ratus whose pulsations are controlled by a resilient, yieldable diaphragm actuated" by changes in volume and pressure of a confined gas.

The device of the present invention is adapted to have a great number of" different applications. For example, it may be used with vacuum cleaners in order to produce pulsations; it may be used with cement mixing apparatus in the construetion of a building, for example; it may be usedin a similar way with-road construction apparatus or with apparatus for constructingcement blocks in orderto speed the drying time; or it may be used in the plastics industry in connection with the fillings of molds and the elimination of air holes; and the device-may similarly be used'with the casting of metal.

One of the objects of the present invention, is to provide a vacuum breaker which is of an extremely simple constructionand easily adapts. able for various diverse-uses as, for example, those mentioned above. Heretofore .it has. been necessary to construct vacuum breakers differently depending onthe purpose for which; they were used. In addition to. being; constructed difiierently from the above-mentioned uses,- vacu-um breakers were constructed 'diiferently depending on whetherthey were to. be used with milking machines, automatic "bottle flllingapparatus, iiquidpumps, etc.. Howeverthefmesent invention aims to provide a vacuum. brea or which may be used for these la,tter-,purposes;aswell as for those mentioned above without;- any changes in the construction thereof so that; itis unnecessary to provide a great number ofcoinplicated: elements which. cause frequent breakdowns.

Another object of the present inyentioniisto v provide a means for holding the flexible diaphragm. of the vacuum breakerin-the vacuum breaking position for a predetermined length of time independently of the difierential. ingas pressures on opposite sides ot thediaphragm.

A further object of the present, invention is to provide a vaouum breaker capable} of accorne plishing the above objectswhilebeing fully autos matic in operation.

A still further object :of thepresentinyention is to provide a means for adjustingthetension in the diaphragm so; as to control the pressure at which the vacuum isbrokent Yet another object ofithe present, invention is to provide ameans foradjustingjhe. length of :time during which the. vacuumv remains,

broken.

phragm so' that diiierent diaphragms may be used with the same apparatus.

With the above objects in view the present invention mainly consists of a vacuum breaker having an outer hollow casing formed with an opening passing therethrough for admitting gas to the interior of the casing. Within thiscasingthere is mounted a resilient flexible diaphragm which, in one position thereof covers the opening in the casing and in another position thereof uncovers this opening, the diaphragm being spaced at a portion thereof-from the casing toform'therewith a passage through which gas-may enter to the-interior of the casing.

A duct communicates with the interior of the casing and is adapted to be connected to a vacuum pump for producing a partial vacuum in the casing, this duct having a free open end located inthe interior of the casing adjacent to the diaphragm on the opposite sidethereof from the opening in the casing. A gas enclosure having a wal-l thereof facing the free open end of the duct is joined to-the diaphragm and covers the free openend of the duct when the. gas in the 'gas enclosure expands and the diaphragm moves away from the-opening in the. casing. In this way the duct is closed by the wall of the gas enclosure until the gas therein contracts to-permit the duct to become uncovered so that the diaphragm snaps back to the position where it closes the opening in the casing to again prevent the entrance of gas thereto and to. permit a partial vacuum to again be produced in the casing-by the vacuum. pump connected to the duct. Means are provided for adjusting the gas pressure in the gas enclosure, the tension in thediaphragm, and the distance of the free open end of the-duct fromthe gas. enclosure so that the pressures at which the diaphragm moves to admit gas to the. casing. and to prevent the entrance of gas thereto. may be easily and accurately regulated.

The novel. features which are considered as characteristicfor the invention are set forth in particular in the. appended. claims. The'invention itself, however, both as to its construction and-its method of operation, together'with addi-. tional objects andadvantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a sectional elevational view through OnepOssibIeapparatus for carrying out the present. invention;

Fig. 2 is a fragmentary top plan view taken along line 22 of Fig. 1 in the direction of the arrows;

Fig. 3 is an illustration of the structure of Fig. 1 in a different position from that shown in Fig. 1;

Fig. 4 is a side sectional view of another embodiment of a construction adapted to carry out the present invention;

Fig. 5 shows the structure of Fig. 4 in a different position from that shown in Fig. 4; and

Fig. 6 shows still another embodiment of the present invention.

Referring now to the drawings, Fig. 1 shows an outer substantially spherical casing it formed from two flanged, substantially hemispherical shells H and I2 which are clamped together at their flanges, any suitable sealing means, such as a gasket I? or the like, being located between the flanges of shells and I2 to seal the interior of the casing It at the joint between shells H and |2. The casing portion Ii is formed with an inlet opening [4, which in the example of Fig. 1 takes the form of a tube 5, and the shell portion 12 is formed with a pair of openings E5 and ll. A threaded tube H5 is permanently connected to the opening H5 and is adapted to be connected to an apparatus with which the device of the present invention is to be used.

An internally threaded member li-l is fixedly connected to the opening I1 and threadedly supports therein a duct 20 which is adapted to be connected to a vacuum pump (not shown) for producing a vacuum in the interior of the casing 0. By means of the threaded connection of duct .26, the position or its free open end 2| in the casing it may be adjusted, and this free open end 2| may have a reduced cross-section as com- Fir pared to the remainder of duct '20, as is illustrated in Fig. 1.

Fixedly mounted on the interior of casing portion I] is a circular, substantially conically shaped plate 22 having an open end 23 fixedly connected to the bottom of tube [5 on the interior thereof, by means of welding or the like, to form l with the tube l5 a tubular means for conveying gas to the interior of the casing H3. The plat-e 22 is provided with a plurality of apertures 24 none of which are located at the open end portion 23 thereof.

Within the casing it on the underside of plate .22 there is located a resilient, flexible diaphragm 25 made of rubber or any other suitable plastic. This diaphragm is fixedly mounted adjacent its periphery on the plate 24 by means, for example, of a ring 26 and aplurality of screws passing through the ring 26, the diaphragm 25 and threadedly engaging threaded openings in the plate 22. The diaphragm 25 is thus movable toward and away from the plate 22 at all points except at a circular portion adjacent the periphery of the diaphragm.

As is shown in Fig. 1, diaphragm 25 has an extension 2! projecting into the interior of tube l5 and resiliently bearing against the open end portion 23 of plate 22 to close the interior of the casing I0 and prevent theadmission of gas thereto through the tubular means I5, 23.

A bar 28 (Fig. 2) is fixedly mounted on the top end of tube I5 without closing the latter and is formed with a threaded opening in which a screw 29 is located, this screw having an enlarged bottom end 30 located within a cup-shaped member 3| fixed to the end portion of extension 21 of diaphragm 25 by means of a pin 32. The part 4 of diaphragm 25 to which pin 32 is connected may be made of a material less resilient than the rest of the diaphragm, in a manner well-known in the art.

The diaphragm 25 is formed with a hollow space 33 covered by a relatively thin, flexible wall 34 joined to the diaphragm and made of the same material as the latter, the wall 34 in the embodiment of Fig. 1 being integral with the diaphragm. Thus, the diaphragm forms with the wall 34 a gas enclosure enclosing a gas which automatically expands and contracts with changes of pressure in the casing H1.

The above described structure operates as follows:

Assuming that element 18 is connected to a device with which the above apparatus is being .used and that duct 20 is connected to a vacuum pump, the apparatus with the parts thereof in the position shown in Fig. l is in the condition where the diaphragm 25 engages the open end 23 of plate 22 about the entire periphery thereof to seal the tubular means I5, 23 and thereby prevent the entrance of gas into the interior of the casing ID from the outside thereof. Thus, the operation of the vacuum pump (not shown) connected to the duct 20 causes the gas pressure within the casing ill to drop, and with this drop in gas pressure the gas within the enclosure 33 will automatically expand and cause the wall portion 34 of enclosure 33 to become distended to- .ward the open end 2| of duct 20.

When the gas pressure within the casing H! has dropped sufiiciently, the pressure differential on the diaphragm 25 will cause the latter to move downwardly, as viewed in Fig. 1, and the suction in duct 29 will contribute to this effect by drawing the distended wall 34 into the opening 2| to cover the latter and seal the duct 20, the suction in the latter maintaining the wall portion 34 over the opening 2| to close the latter, as is illustrated in Fig. 3. When the parts are in the condition shown in Fig. 3, gas from the outside of easing l 0 enters through tubular means I5, 23 and openings 24 in the plate 22, some of these openings being located below the diaphragm 25, as viewed in Fig. 1, so that the gas on the outside of casing 10 enters into the latter and causes the gas pressure therein to rise. The diaphragm 25 will be maintained in the position shown in Fig. 3 for a longer time than it would if the apparatus .were not provided with the gas enclosure 33 because of the maintenance of wall 34 over the .opening 2| by the suction in duct 20. As the gas pressure in the casing l0 rises, the gas in en closure 33 automatically contracts and the wall .portion 34 gradually contracts until it opens the opening 2|, at which time the diaphragm 25 snaps back to the position shown in Fig. 1 under the action of the resilient force inherent in the material of the diaphragm.

This latter force may be regulated by the turning of screw 29 which causes the extension 21 of diaphragm 25 to become stretched to a predetermined extent so that the diaphragm will not move from the position of Fig. 1 to that of Fig. 3 until the pressure within the casing 0 falls below I a predetermined value, the screw 29 thus serving 5 29 in the internally threadedfitting l9- so that the open end2l of duct-Z is located at a predetermined distance from the gas enclosure 33.

Thus, when the open end 2| of duct 24) is located relatively near to wall 34,-the extension 2? will be tensioned to a relatively low degree and. the gas in the enclosure 33 will contract considerably before the tension in wall portion 3 will become sufliciently reduced to cause the opening 2i to become uncovered, so that the pressure at which the diaphragm 25 closes the casing ID will be relatively high. On the other hand, if the free open end 2! of duct 20 is located relatively far from the enclosure 33, the extension 2'! will be tensioned to a relatively high degree and. the stretched wall 34 need only have the tension therein reduced by a relatively small amount before uncovering the opening 2!, and in this position of the parts the pressure at which the diaphragm will move back in the position shown in Fig. 1 will be relatively low. Thus the above described structure is capable not only of producing pulsations, but it is also capable of accurately controlling these pulsations through a simple and automatic structure, and the time during which the diaphragm 25 is maintained in the position shown in Fig. 3 iseasily regulated by the position of duct 26 and screw 29.

Figs. 4 and 5 illustrate a modified embodiment of the apparatus shown in Figs. 1 and 3 in positions respectively corresponding to those of Figs. 1 and 3. In the apparatus of Figs. 4 and 5, the casing it is formed with an opening 44 in which the neck of an apertured plate 32 similar to plate 22 is located. A tube 43 having opposite open ends is threadedly mounted in the internally threaded necl: of plate 42. This apertgired plate 12 is provided with flange it clamped between the flanges oi the half shells of casing MI, and this flange it is formed with some of the apertures 65 which are distributed in the plate 42. Fixedly mounted. on the flange 44 is a resilient diaphragm 46, which in the embodiment of Fig. 4 is substantially hemispherical in shape and has an inwardly extending annular flange fixed to the flange (it by any suitable means, such as a ring dl' having screws passing therethrough, through the annular flange of diaphragm it and engaging threaded openings in the flange 45 of plate d2.

A dished wall 33 of resilient, stretchable material, which may be the same material as that of diaphragm at, but may have a different thickness or may be a different material with difierent properties, is joined at its periphery to the underside of diaphragm 4 6, as shown in Fig. 4, the joint between elements 46 and 48:. being carried out in any suitable way, such asby'fusing elements and 48 together in a mannerswell known in the plastics art. Thus,.the member '48 forms with a part of the diaphragm 46: a. gas enclosure similar to enclosure 33 desc1'ibed.:above, and the wall 48 has removably mounted thereon a plug t9 so that the pressure and gas within the enclosure 5:? formed b diaphragm 46 and wall it may be regulated, when the plug it is. removed, and kept in its regulated condition by replacing t9 so as to seal the enclosure 553. The plug 49 may be or any suitable construction. For example, an internally threaded ring 5| of relatively small diameter may be joined to the wall 53 and removably support the plug 59 which is externally threaded and in engagement with the threads of ring 5 l.

The tubular member 43 is located so that its lower open end isclosed by d aphragmtt when the latter is in the position shown in Fig. 4 and opened when diaphragm 56 is shown in the position of Fig. 5. The pressure at which the diaphragm it will open the tube it to permit gas to enter the casing li} may be regulated by turning of tube 43. Thus when the latter is adjusted in the position where its lower end, as viewed in Fig. 4, is located relatively near to the opening ll of easing it, the diaphragm cs will only move through a relatively small distance before opening the tube 53 so that the pressure in casing 40 at which gas is admitted to the latter will be relatively high. However, when the lower end of tube 43, as viewed in Fig. i, is located well within the casing it and at a substantially larg distance from opening ii, the diaphragm 56 will necessarily movethrough a relativel large distance before uncovering the tube is, and therefore the pressure in casing ll: will be relatively low before the vacuum therein is broken.

Also, by turning member 43 toward or away from enclosure 59, the space therein can be displaced to initially locate wall i3 respectively .nearerto or farther from end 53 of duct 52 to provide an additional adjustment of the device.

The vacuum in casing ii] is produced by a duct 52 connected to a vacuum pump (not shown) and adjustably mounted on the casing til in the same way that duct it; is mounted on casing iii, the only difierence between ducts 2i! and 52 being that the free open end 53 of the latter is not of a reduced cross-section. As the pressure in casin '40 is reduced by the suction in duct 52, the gas in enclosure iii expands to cause the wall 48 to become distended toward th open end 53 of duct 52, this wall 48 closing opening 53 and being held over the latter by the suction in tube 52 until the gas pressure in casing it rises above a predeterined value in the same as with the embodiment of Figs. 1 and 3. The adjustment of'tube 52 in casing controls the extent to which pressure rises in the casing iii, and with the embodiment of Fig. the time when the tube becomes closed may be regulated more accurately than with the embodiment of Figs. 1 and 3 because the gas in enclosure 5i! may be independently controlled by changing the insid pressure.

Afurther embodiment of the invention is illustrated in Fig. (i, this embodiment combining an adjusting means similar to that of Figs. 1 and 3, for adjusting the tension in the resilient diaphragm, and the feature of 4.- whereby the gas pressure within the gas enclosure may be regulated. The casing 69 and plate 6i of the structure of Fig. 6 are iden ical with the casing 40 and plate d2 of Fig. 4 except that the neck 62 of plate iii is longer than the neck of plate 42 and is not internally threaded. This neck 62 is closed at its top by a plate 63 having a central aperture through which a rigid tube 5 3 extends, and the neck 82 is formed with a side opening in which the tube 65 is mounted to conduct gas to the interior of casing 6% through the neck 62 which forms a tubular means similar to tubular means i5, 23 of Figs. 1 and 3.

The diaphragm S6 is provided with an inwardly extending annular flange iii mounted on the plate 61 in the same way that diaphragm is mounted on plate 52. The top portion of the diaphragm 66 is provided with a resilient tubular extension 68 made of the same material as the diaphragm 6G and fixedly joined to the lower end portion of tube 6 5, as viewed in Fig. 6, by any suitable means such as the ring 89 which clamps the topend portion of extension 63 to the tube 84. If desired, extension 68 may be of a different thickness than diaphragm 66 or may be of a diiferent stretchable material having different properties. The top end of the tube 64 is internally threaded and removably supports an externally threaded plug which seals the extension 68 and tube 64 from the gas on the outside of casing 60. A wall H similar to wall 48, except that it is not provided with a removable plug, is joined to the underside of diaphragm 60, as shown in Fig. 6, so that this wall N forms together with the upper portion of diaphragm 66, extension 68 and tube 64 a gas enclosure '12, similar to the gas enclosures 33 and 50, which may have the gas therein controlled by removal of plug 10.

The sealing of the casing 60 is brought about by the resilient pressure of diaphragm 66 against the lower end of neck 62. A collar 13 is mounted about the tube 64 and fixed at a predetermined position along the length thereof by means of a set screw 74, this collar 13 being maintained against the cover 63 of neck 62 by the resilient force of the diaphragm 66 with its extension 68. Thus, by locating the collar 13 nearer to the lower end of tube E24, as viewed in Fig. 6, the tension in extension 68 and diaphragm 66 may be increased in the same way that the tension in extension 2! of diaphragm 25 is regulated by turning of screw 29, in the embodiment illustrated in Figs. 1 and 3, so as to vary the force with-Which the diaphragm 66 bears against the lower end of neck 62 to close the latter and seal the interior of casing 60.

The suction duct 75 is adapted to be connected to a vacuum pump (not shown) for producing a partial vacuum within the casing 60, and is adjustably mounted in the same way as duct 52 to cooperate with wall H in the manner described above, the gas in enclosure 12 expanding and contracting to distend the wall H which covers and uncovers the open free end 16 of duct in the same way as in the embodiments described above. The embodiment of Fig. 6 operates in exactly the same way as in the above described embodiments of the invention to produce the same results.

It will be noted that in all of the above-described embodiments the resilient diaphragms are removably mounted so as to be exchangeable with other diaphragms. In this way any of the above-described embodiments may be provided with diaphragms of different properties and/or materials suited for a particular use to which the invention is applied.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of vacuum breakers difiering from the types described above.

While the invention has been illustrated and described as embodied in adjustable vacuum breakers, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention, and therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. Vacuum breaking apparatus, comprising, in combination, a hollow casing formed with an opening in a wall thereof; automatic valve means associated with said opening and being mounted on said casing for automatic movement between a closing position preventing the passage of gas through said opening and an open position permitting the passage of gas through said opening, said valve means being automatically movable into said open position when gas pressure in said casing decreases below a first predetermined value and said valve means including a resilient portion urging the same into said closing position thereof when the gas pressure in said casing rises above said first predetermined value; duct means communicating with said casing and adapted to be connected to a vacuum pump for reducing the gas pressure in said casing below said first predetermined value so as to produce a partial vacuum in said casing and cause said valve means to automatically move against the action of said resilient portion thereof into said open position; and pressure sensitive closure means communicating with the interior of said casing to be actuated by the pressure therein, and connected to said automatic valve means for movement therewith, and being associated with said duct means to close the same when said valve means is in said open position thereof and to maintain said duct means closed and said valve means in said open position until the gas pressure in said casing rises above a second predetermined value higher than said first predetermined value, said resilient portion of said automatic valve means moving the latter into said closed position thereof when the gas pressure in said casing rises above said second predetermined value.

2. Vacuum breaking apparatus, comprising, in combination, a hollow casing formed with an opening in a wall thereof; automatic valve means associated with said opening and being mounted on said casing for automatic movement between a closing position preventing the passage of gas through said opening and an open position permitting the passage of gas through said opening, said valve means being automatically movable into said open position when gas pressure in said casing decreases below a first predetermined value and said valve means including a resilient portion urging the same into said closing position thereof when the gas pressure in said casing rises above said first predetermined value; duct means communicating with said casing and adapted to be connected to a vacuum pump for reducing the gas pressure in said casing below said first predetermined value so as to produce a partial vacuum in said casing and cause said valve means to automatically move against the action of said resilient portion thereof into said open position; pressure sensitive closure means communicating with the interior of said casing to be actuated by the pressure therein, and connected to said automatic valve means for movement therewith, and being associated with said duct means to close the some when said valve means is in said open position thereof and to maintain said duct means closed and said valve means in said open position until the gas pressure in said casing rises above 'a second predetermined value higher than said first predetermined value, said resilient portion of said automotive valve means moving the latter into said closed position thereof when the gas pressure in said casing rises above said second predetermined value; and adjusting means connected to said valve means for setting said first predetermined value.

3. Vacuum breaking apparatus, comprising, in combination, a hollow casing; first duct means communicating with the interior of casing to convey gas to the same; a resilient diaphragm supported in said casing with a portion thereof spaced from said casing and forming therewith a passage for gas from said first duct means into the interior of said casing, said diaphragm being located over said first duct means to close the same and being movable away from said first duct means to open the same; second duct means having a free open en in the interior of said casing and being adapted to be connected to a vacuum pump for producing a partial vacuum in said casing to cause said diaphragm to automatically move away from and open said first duct means when the pressure in said casing falls below a predetermined value; a flexible resilient enclosure having a wall thereof joined to said diaphragm and facing said free open end of said second duct means, said enclosure trapping a gas between itself and said diaphragm so that, when the gas in said enclosure expands and'said diaphragm moves away from said first duct means, said wall of said enclosure moves toward and covers said second duct means.

4. Vacuum breaking apparatus, comprising, in combination, a hollow casing; first duct means communicating with the interior of casing to convey gas to the same; a resilient diaphragm supported in said casing with a portion thereof spaced from said casing and forming therewith a passage for gas from said first duct means into the interior of said casing, said diaphragm being located over said first duct means to close the same and being movable away from said first duct means to open the same; second duct means having a free open end in the interior of said casing on the opposite side of said diaphragm from said first duct means, said second duct means being adapted to be connected to a vacuum pump for producing a partial vacuum in said casing to cause said diaphragm to automatically move away from and open said first duct means when the pressure in said casing falls below a prcdetermined value; a flexible resilient enclosure having wall thereof joined to said diaphragm and facing said free open end of said second duct means, enclosure trapping a gas between itself and said so that, when the gas in said enclosure expands and said diaphragm moves away from said first duct means, said wail of said enclosure moves toward and covers said second duct means.

5. Vacuum breaking apparatus, comprising, in combination, a hollow casing; first duct means communicating with the interior of said casing to convey gas to the same; a plate fixedly mounted in said casing and having a portion extend ing into said casing and formed with an opening passing therethrough; a resilient diaphragm supported on said plate in said casing away from said opening in said plate, said diaphragm having a portion thereof spaced from said casing and forming therewith a passage for gas from said first duct means into the interior of said casing, said diaphragm being located over said first duct means to close the same and being movable away from said first duct means to open the same; second duct means having a free open end in the interior of said, casing on the opposite side of said diaphragm from said first duct means, said second duct .means being adapted to be connected to a vacuum pump for producing a partial vacuum in said casing to cause said diaphragm to automatically move away from and open said first duct means when the pressure in said casing falls below a predetermined value; a flexible resilient enclosure having a wall thereof joined to said diaphragm and facing said free open end of said second duct means, said enclosure trapping a gas between itself and said diaphragm so that, when the gas in said enclosure expands and said diaphragm moves away from said first duct means, said wall of said enclosure moves toward and covers said second duct means.

6. Vacuum breaking apparatus as defined in claim 5 and wherein said second duct means is adjustably mounted on said casing so that said free open end thereof may be located at a predetermined distance from said wall of said enclosure.

'7. Vacuum breaking apparatus as defined in claim 5 and wherein a plug is removably mounted on said wall of said enclosure so that the gas therein may be controlled.

8. Vacuum breaking apparatus as .definedin claim 5 and wherein part of said, enclosure is formed by a portion of said diaphragm located opposite said wall of said enclosure.

9. Vacuum breaking apparatus as defined in claim 5 and wherein said resilient diaphragm is removably mounted on said plate so that one diaphragm may be exchanged for another.

10. Vacuum breaking apparatus, comprising, in combination, a hollow casing formed with an opening passing therethrough; tubular means joined to said opening of said casing for conveying gas to the interior thereof; a plate fixedly mounted in said casing distant from said tubular means and being formed with an aperture passing therethrough; a resilient, flexible diaphragm fixedly mounted on said plate, away from said aperture thereof, in the interior of said casing and resiliently pressing against said tubular means to close the same, said diaphragm having an extension projecting into said tubular means; duct means communicating with the interior of said casing and being adapted to be connected to a vacuum pump for producing a partial vacuum in said casing, said duct means having a free open end located adjacent to said diaphragm on the opposite side thereof from said tubular means; and a gas enclosure having a wall thereof joined to said diaphragm and located opposite said free open end of said duct means.

11. Vacuum breaking apparatus, comprising, in combination, a hollow casing formed with an opening passing therethrough; tubular means joined to said opening of said casing for conveying to the interior thereof; a plate fixedly mounted in said casing distant from said tubular means and being formed with an aperture passing therethrough; a resilient, flexible diaphragm fixedly mounted on said plate, away from said aperture thereof, in the interior of said casing and resiliently pressing against said tubular means to close the same, said diaphragm having an extension projecting into said tubular means; duct means communicating with the interior of said casing and being adapted to be connected to a vacuum pump for producing a partial vacuum in said casing, said duct means having a free open end located adjacent to said diaphragm on the opposite side thereof from said tubular means; and a gas enclosure having a wall thereof joined to said diaphragm and located opposite said free open end of said duct means, said gas enclosure being partly formed from a portion of said diaphragm located opposite said Wall of said enclosure.

12. Vacuum breaking apparatus, comprising, in combination, a hollow casing formed with an opening passing therethrough; tubular means joined to said opening of said casing for conveying gas to the interior thereof; a plate fixedly mounted in said casing distant from said tubular means and being formed with an aperture passing therethrough; a resilient, flexible diaphragm fixedly mounted on said plate, away from said aperture thereof, in the interior of said casing and resiliently pressing against said tubular means to close the same, said diaphragm having an extension projecting into said tubular means; duct means communicating with the interior of said casing and being adapted to be connected to a vacuum pump for producing a partial vacuum in said casing, said duct means having a free open end located adjacent to said diaphragm on the opposite side thereof from said tubular means; a gas enclosure having a wall thereof joined to said diaphragm and located opposite said free open end of said duct means, said gas 12 enclosure being partly formed from a portion of said diaphragm located opposite said wall of said enclosure; and adjusting means mounted on said tubular means and being operatively connected to said extension of said diaphragm to adjust the tension therein and thereby adjust the force with which said diaphragm bears against said tubular means.

13. Vacuum breaking apparatus as defined in claim 10 and wherein said extension of said diaphragm is hollow and communicates with the interior of said gas enclosure.

14. Vacuum breaking apparatus as defined in claim 13 and wherein a closure means is associated with said hollow extension of said diaphragm to open and close the same for controlling the gas in said gas enclosure.

15. Vacuum breaking apparatus as defined in claim 10 and wherein said duct means is adjustably mounted on said casing so that said free open end of said duct means may be located at a predetermined distance from said wall of said enclosure.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,400,512 Barden Dec. 20, 1921 1,680,368 Douglas Aug. 14, 1923 2,086,868 Hall July 13, 1937 2,292,401 Orre Aug. 11, 1942 

